Art of measuring distances between two undersea points remotely

ABSTRACT

A GAUGE IS DISCLOSED CAPABLE OF MEASURING DISTANCES BETWEEN A VERTICALLY EXTENDING UNDERSEA WELLHEAD AND AN UPWARDLY EXTENDING UNDERSEA RECEIVING PIPE SO THAT A CONNECTING TUBING LOOP COULD BE FABRICATED TO CONNECT THE TWO. THE GAUGE HAS A CONNECTOR WHICH SITS ON THE WELLHEAD, AND A FEELER, FOR MAKING CONTACT WITH THE PIPE. THE CONNECTOR AND FEELER ARE CONNECTED BY A FRAME THAT ALLOWS THE FEELER TO MOVE IN TWO ORTHOGONAL DIRECTIONS RELATIVE TO THE CONNECTOR. THE GAUGE IS LOWERED TO THE SEA FLOOR SO THAT GUIDE SLEEVES FIXED TO THE CONNECTOR ENGAGE VERTICAL GUIDE PINS AROUND THE WELLHEAD AND SO THAT GUIDE SLEEVES FIXED TO THE FEELER ENGAGE OTHER GUIDE PINS AROUND THE PIPE. THE CONNECTOR ENGAGES THE WELLHEAD FIRST AND THEN AN ELECTRIC MOTOR LOWERS THE FRAME AND FEELER. WHEN THE FEELER CONTACTS THE PIPE, THE MOTOR IS STOPPED AND LOCKED IN PLACE, PROVIDING AN INDICATION OF THE SPACING IN THE VERTICAL DIRECTION. A MARKER IS PROVIDED TO MARK THE FRAME WITH RESPECT TO THE FEELER TO INDICATE THE SPACING BETWEEN THE CONNECTOR AND FEELER IN THE HORIZONTAL DIRECTION AND THE ANGULAR DEVIATION BETWEEN CENTER-LINES OF WELLHEAD GUIDE PINS AND THE GUIDE PINS ASSOCIATED WITH THE RECEIVING PIPE.

Set. 20, 1971 Filed Jan. 2. 1970 W. BROWN ART OF MEASURING DISTANCES BETWEEN TWO UNDERSEA POINTS REMOTELY 2 Sheets-Sheet 1 INVENTOR.

WALTER BROWN Sept. 20, 1971 w. BROWN 3,605,270

- ART OF IEASURING DISTANCES BETWEEN TWO UNDERSEA POINTS REMOTELY Filed Jan. 2, 1970 2 Sheets-Sheet I INVENTOR.

WALTER BROWN 2BY a m United States Patent U.S. CL 33-174 8 Claims ABSTRACT OF THE DISCLOSURE A gauge is disclosed capable of measuring distances between a vertically extending undersea wellhead and an upwardly extending undersea receiving pipe so that a connecting tubing loop could be fabricated to connect the two. The gauge has a connector which sits on the wellhead, and a feeler, for making contact with the pipe. The connector and feeler are connected by a frame that allows the feeler to move in two orthogonal directions relative to the connector. The gauge is lowered to the sea floor so that guide sleeves fixed to the connector engage vertical guide pins around the wellhead and so that guide sleeves fixed to the feeler engage other guide pins around the pipe. The connector engages the wellhead first and then an electric motor lowers the frame and rfeeler. When the feeler contacts the pipe, the motor is stopped and locked in place, providing an indication of the spacing in the vertical direction- A marker is provided to mark the frame with respect to the feeler to indicate the spacing between the connector and feeler in the horizontal direction and the angular deviation between center-lines of wellhead guide pins and the guide pins associated with the receiving pipe.

This invention relates ot the art of measuring distances under water remotely from the surface thereof.

There is disclosed, in a copending U.S. patent application Ser. No. 717,761, filed on Apr. 1, 1968, and assigned to the same assignee as this application, a system for operating and servicing oil wells located on the ocean floor. The system includes a plurality of wellheads located on the circumference of a large circle having, for example, a forty-foot diameter. At the center of the circle is located a pressure vessel, that is capable of sustaining life, storing well equipment and tools, and also storing crude oil temporarily. The pressure vessel is connected to each well by a tubing loop assembly containing suitable tubing through which petroleum products flow from the well to the vessel and throughflow-line servicing equipment and tools move from the pressure vessel to the wells and back to the vessel. Although the above mentioned application teaches that the assembly should be flexible to take care of slight misalignment problems, an actual system will encounter major misalignment problems. For example, since the wellheads could be located at 2000 or more feet underwater, the wellhead could be within plus or minus five feet of the circumference of the 40-foot diameter circle. In addition, the sea floor could be sloped whereby a slight slope of five degrees could produce an error of about three feet in the calculated distance between the wellhead and the connecting pipe on the vessel. Obviously, a tubing loop assembly, with a flexibility capable of taking up such wide tolerances, is clumsy to handle and expensive to build.

Therefore, an object of this invention is to provide a means for measuring remotely distance between two points located underwater and the horizontal angular deviation between two connecting faces.

Another object is to provide a simple expandable frame that expands in two orthogonal directions and can be lowered to the ocean floor to engage both a wellhead and 3,665,27 Patented Sept. 20, 1971 a pipe spaced therefrom, and which frame has means for permanently marking the degree of expansion and the angular relationship when engagement is made so that the same shape can be reproduced in the frame when the frame is lifted out of the water.

These and other objects and features of advantage of this invention will become better understood by reference to the following detailed description when considered together with the drawings, in which:

FIG. 1 is an elevation in schematic of a typical undersea crude oil production system wherein the teachings of this invention are particularly useful;

FIG. 2 is an elevation of the novel measurement gauge made in accordance with the teachings of this invention;

FIG. 3 is a plan view of the gauge in FIG. 2; and

FIG. 4 is a side view of the left side of a portion of the gauge shown in FIG. 2.

Referring to the drawings and to FIG. 1 in particular, there is shown a typical crude oil production system in which this invention has utility. However the usefulness of the invention is not limited to the particular system. The system has a plurality of wellheads 1 arranged in a circle. The wellheads 1 are located on or near the ocean floor that is, for example, 2000 feet below the surface of the ocean. The function of the system is to collect the petroleum products within a pressure vessel 2 located at the center of the wellheads. As disclosed in the above mentioned application, the pressure vessel 2 is hollow and has enclosed liveable quarters and storage tanks. The pressure vessel has a plurality of connecting pipe assemblies 35, each of which connect to a particular wellhead 1 through a tubing loop assembly 3. The tubing loop assembly 3 may have more than one tube as required which tubes terminate at a collet connector 3a at one end and collet connector 3b at the other end. Connector 3a connects to one of the wellheads 1 and connector 3b connects to one of the connecting pipe assemblies 35. The ocean floor is shown sloping in order to illustrate the difference between the vertical distance from the wellhead on the right to its connecting pipe" assembly and the distance from the wellhead on the left to its connecting pipe assembly. This difference as explained above is inherently large.

Referring to FIGS. 2 and 3 a novel gauge is shown for measuring or determining the distance between a wellhead and its connecting pipe assembly so that an assembly 3 can be custom built for the particular well. The typical system shown in FIG. 1 includes, for example, three guide pins 39 (more clearly shown in FIG. 3) which are fixed around each of the wellheads 1, and includes guide pins 37 on the pressure vessel 2. In particular, there are two pins 37 associated with each connecting pipe assembly 35. In addition, guide lines 40 extend from pins 39 to the ocean surface and guide lines 38 extend from pins 37 to the ocean surface. The above mentioned application teaches the combination of the pins and guide lines with the system. The guide lines are used to guide the gauge in place as shown, by threading guide lines 40 into respective guide sleeves 4 and lines 38 into guide sleeves 33 and then lowering the gauge over the side of the floating vessel. The sleeves 4 slide over pins 39, guiding a collet connector 3d over the wellhead. Connector 3d being similar to connector 3a is clamped onto the wellhead 1. The guide sleeves 4 are connected to the connector 3d by arms 5. Extending upward from connector 3d is a cylindrical column 6 secured thereto by a flange 7. Slidably and rotatively mounted on column 6 is a sleeve 8 which is journaled on bushings 11 located at each end of sleeve 8 and one of which is shown in FIG. 4. A snug fit is formed so that a relatively large force is needed to slide or turn sleeve 8 relative to column 6. The lower end of sleeve 8 engages a flange 9 which is prevented from turning columns 6 by a suitable and slidable key (not shown) engaging a keyway 10 on the column 6. Flange 9 has two female threads that engage a pair of self locking screws 13 which are journaled in bores formed in a flange 15, and are prevented from axial movement by collars 14. Flange 15 is welded to column 6. The lower ends of screws 13 have gears 16 which engage a ring gear 17 journaled to column 6. One of the screws 13 is connected to the shaft of preferably an electric brake motor 19 mounted to column 6 so that when the motor rotates the sleeve 8 moves axially along the column. An electric brake motor is a commercially available item wherein an electric motor has a built in brake which is automatically applied when the current is cut off.

Extending laterally or horizontally from sleeve 8 is a pipe feeler 34 which is supported by a triangle brace or frame made of links 23 and 24, with sleeve 8 making the third link. The three links are connected together by pins 20, 21, and 22. The pipe feeler 34 is mounted to the brace and to link 23, in particular, so that the feeler 34 is free to move radially towards or away from column 6. The feeler is mounted as follows: A trunnion 28 is slidably and rotatively supported on link 23 by bearings 25 and 26. On the outer end of the trunnion 28 is formed a yoke 27 rotatively supporting a cross shaft 29 by bearings including covers 36. One guide sleeve 33 is fixed to each end of the cross shaft 29. The pipe feeler 34 is attached to the center of the shaft 29 by an arm 32. Shaft 29 has collars and thrust rings 31 to prevent axial movement of the cross shaft 29 with respect to the yoke 27. To the other end of the trunnion 28 is fixed a drum 41 having an extension shaft 42 journaled in a bearing 43. The drum 41 is covered with a layer of plastic or soft metal so that a mark can be formed thereon by a stylus 44 which is fixed to link 23 and is capable of being urged against the drum 41, for example, by remotely detonating a charge in a manner well known in the art to form a mark on the drum 41. To easily read the amount of deviation in the frame the drum 41 is preferably marked with grid lines (not shown), one set oriented to run eircurnferentially around the drum 41 and the other set disposed normal thereto and also parallel to the drum axis.

The gauge is operated as follows: With the sleeve 8 disposed in its furthest position from connector 3d the gauge is lowered down the guide lines, for example, by attaching a drill pipe on the floating vessel to a cap 45 on the end of column 6. When the connector 3d sits on the wellhead the connector is remotely clamped thereto in a manner described in the prior art. Then motor 19 is started causing the screws 13 to pull down the sleeve 8. As the sleeve 8 moves downward it rotates about the column and trunnion 28 slides axially and rotates to allow the guide sleeve 33 to engage pins 37. On the end of the feeler 34 is located a switch which opens the circuit to the motor 19 stopping the motor when the feeler contacts the pipe 35. The charge on the stylus 44 is detonated to mark the drum 41. The gauge is now lifted out of the water and the trunnion 28 can be relocated with respect to link 23 to its position maintained on the ocean floor when the drum was marked. Since the sleeve 8 is held firmly to column 6, these two need not be relocated. The tubing loop assembly 3 can be fabricated so that connectors 3a and 3b are spaced to readily engage the particular wellhead and pipe connector which was engaged by the gauge.

Although one embodiment of the invention has been described, one skilled in the art after studying the teach- 4 ings herein could make variations that lie within the scope of the invention.

What is claimed is:

1. A measurement gauge for measuring distances underwater between two elements having fixed guide pins and guide lines extending to the surface from each pin, said gauge comprising:

a member,

first means on one end of said member to engage one of said points,

a first pin guide sleeve fixed to said first means and adapted to have one of said guide lines threaded therethrough and to engage one of said pins,

a frame slideably engaging said member,

second means slideably mounted to said frame to engage the other of said points,

a second pin guide sleeve fixed to said second means and adapted to have another one of said guide lines threaded therethrough and to engage another one of said pins, and

third means for marking the relative position of said member and said frame, and

fourth means for marking the relative position of said frame and said second means.

2. The gauge of claim 1 wherein:

said member is elongated,

said frame includes three links pinned together to form a triangle,

one of said links is disposed to slide along said elongated member, and

a trunnion supports said second means, and disposed to slide relative to said frame.

3. The gauge of claim 2 wherein:

said member is further defined as being cylindrical,

said one link is tubular and is further disposed to rotate about said member, and

said trunnion is further disposed to rotate relative to said frame.

4. The gauge of claim 2 wherein:

a rotatable screw is mounted to said member and is fixed parallel with the member,

said screw engaging a female thread formed in said link,

and

a motor mounted to said member to rotate said screw so that said frame slides along said member.

5. The gauge of claim 4 wherein:

said trunnion has disposed a yoke on one end,

said second means is mounted to said yoke to rotate about a substantially horizontal axis,

two pin guide sleeves are fixed to said second means and disposed on opposite sides of said yoke.

6. The gauge of claim 5 wherein:

said frame slides relative to said member in a direction that is orthogonal to the direction said second means slides relative to said frame.

7. The gauge of claim 6 wherein:

said first means is a connector adapted to connect to an underwater wellhead and said second means is a feeler for contacting the end of a pipe disposed at the other point.

8. The gauge of claim 7 wherein:

a drum is disposed on the other end of said trunnion,

and

an explosive activated stylus is disposed to mark said drum when the explosive is activated.

No references cited.

LEONARD FORMAN, Primary Examiner P. G. FOLDES, Assistant Examiner 

